The exemplary embodiments described herein detail for illustrative purposes and are subject to many variations in structure and design. It should be emphasized, however, that the present invention is not limited to a particularly disclosed embodiment shown or described. It is understood that various omissions and substitutions of equivalents are contemplated as circumstances may suggest or render expedient, but these are intended to cover the application or implementation without departing from the spirit or scope of the claims of the present invention. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. The terms “an” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. This disclosure generally relates to a method for producing a display member for an operation button or the like mounted on various kinds of equipments such as an instrument panel or an audio unit for a motor vehicle and relates to a molded product for the display member formed by using a mold.
Recently, a display panel to be mounted on various kinds of equipments such as an instrument panel or an audio unit for a motor vehicle is often provided with an illuminating function on a display section such as characters or figures in order to secure visibility during the night.
A display member provided with such illuminating function has been disclosed in, for example, Patent Document 1. The display member disclosed in Patent Document 1 (“an illuminating key 5” in Patent Document 1) includes a main body made of a resin or the like having light permeability. A painted layer made of a light-shielding paint is applied to a surface on the main body. A part of the painted layer is stripped from the surface on the main body in a manner of a suitable shape. When lights are emitted onto a rear side of the display member, the lights are permitted to pass to a front side of the display member through only an unpainted portion from which the painted layer is stripped. Consequently, it is possible for a user to clearly recognize the shape of the unpainted portion during the night.
However, there is a problem that this display member will be subject to constrains in selection of color on the unpainted portion or the display portion under a non-illumination condition by the following reasons.
Firstly, if a display member main body is completely transparent, there are problems that a difference in brightness between a portion near a light source and a portion remote from the light source becomes remarkable and a part outside an illuminating area may be a see-through shadow due to a visual angle. Accordingly, in order to restrain the uneven brightness caused due to the visual angle on the unpainted portion or the display portion to perform uniform illumination, it is preferable that a material of the display member main body has a light-diffusing function. Specifically, an acrylic resin or an ABS resin that is turned cloudy in milk white is most preferable.
On the other hand, since a surface on the unpainted portion on the display member main body is exposed as it is, a color of the unpainted portion becomes the same as that of the display member main body itself during the daytime when illumination is not effected. It is preferable that a color of a portion to be illuminated can be clearly distinguished from a color of the painted layer. For example, in the case where the color of the painted layer is relatively pale, it is required that the color of the display member main body is selected to be a black-based color. Also, on the matter of design, there is a case where the color of the unpainted portion is desired to be a particular color.
However, as described above, materials of the display member main body are limited, if the material has the light-diffusing function. Under this situation, the color of the display member main body, that is, the color of the unpainted portion during a non-illumination time is subject to considerable constraints. For example, in the case where the acrylic resin or the ABS resin that is turned cloudy in milk white is used for the display member main body, the color of the display member main body is limited to a white-based color by itself.
That is, if a uniform illumination is desired on the conventional display member, there is a problem that a selection of a color on the unpainted portion or the display portion during non-illumination time is remarkably limited.
In order to overcome the above problems, for example, Patent Document 2 has proposed a display member 100 as shown in FIG. 9 (a front elevation view) and FIG. 10 (a rear side elevation view). The display member 100 includes a translucent display member main body 101 and a light-shielding layer 103 for covering an area on a front surface of the display member main body 101 except a particular display section 102. When lights are emitted onto a rear side of the display member main body 101, the lights pass the area on which the light-shielding layer 103 is not provided and illuminates the front surface of the main body 101.
The display member main body 101 comprises a light-diffusing layer 106 and a transparent layer 105 that are laminated on each other. The light-diffusing layer 106 has a light-diffusing effect and is disposed on a rear side of at least the particular section 102 to cover it. The transparent layer 105 is disposed on a front side of the light-diffusing layer 106, has a higher transparency than that of the light-diffusing layer 106, and is colored with a particular color.
The lights emitted onto the rear side of the display member main body 101 of the display member 100 pass the light-diffusing layer 106 and transparent layer 105 on the display member main body 101, further pass only the display section 102, on which the light-shielding layer 103 is not provided, and come out from a front side of the display section 102. Accordingly, the shape of the display section 102 is clearly illuminated and a uniform illumination having no uneven brightness can be realized by a light-diffusing effect of the light-diffusing layer 106. In addition, even if the color on the light-diffusing layer 106 is limited (for example, even if the light-diffusing layer is made cloudy in milk white), it is possible to set the color of the display member main body 101 during a non-illustrating time (that is, a color on the portion on which the light-shielding layer 103 is not provided) to be a desired color or a color similar to the desired color.
However, the display member 100 has the following problems with respect to a matter in production.
The display member 100 is produced by the following steps. Firstly, as shown in FIG. 11, the light-diffusing layer 106 is formed primarily by using a mold (not shown) and the transparent layer 105 is formed secondly by using the mold. The layers 105 and 106 are integrated with each other to form the display member main body 101. Then, the display member main body 101 is removed from the mold and a runner coupled to the transparent layer 5 is cut out. A light-shielding material is sprayed onto display member main body 101 from a front side of the main body 101 (a side of the transparent layer 105) and a side surface perpendicular to the front side (an outside of at least the portion from which the runner is removed) to form the light-shielding layer 103.
In the above producing steps, the runner 104, for example, as shown in FIGS. 11 and 12, includes a proximal end 104a connected to a rear surface of the outer transparent layer 105 on the display member main body 101, and a distal end 104b that extends outward from the proximal end 104a in a direction substantially perpendicular to a bottom surface 105a of the transparent layer 105. The runner 104 has a substantially uniform area in cross section from a lower side of the proximal end 104a to the distal end 104b. The runner 104 is cut out by a cutting means such as a nipper. However, as shown in FIG. 13, a part of the proximal end 104a remains in the transparent layer 105. In addition, since the runner 104 is cut out along the bottom surface 105a of the transparent layer 105 in a direction perpendicular to the runner 104, a remainder chip 104c from the proximal end 104a projects backward greatly from the rear side of the proximal end 104a and interferes with a painting step of the light-shield layer 103. Consequently, faults of painting will be caused on an inner part surface (an upper surface) A of the remainder chip 104c and on a rear surface B of the transparent layer 105 located at a further inner part from the remainder chip 104c. This will cause a problem that a portion having no light-shielding layer 103 remains. This will be caused by spraying the paint onto the remainder chip 104c from its outside in order to form the light-shielding layer 103.
Such remainder chip 104c and faults of the light-shielding layer 103 on the transparent layer 105 will permit the lights to leak from remainder chip 104c of the runner 104 and the transparent layer 105 regardless of the fact that the remainder chip 104 and the faults are different parts from the display section 102 itself. This will be a cause of impeding a suitable display.    Patent Document 1: JUM HEI 6 (1994)-38127 CD-ROM    Patent Document 2: JP 2005-338499A